1. Field of the Invention
This invention relates to thermoplastic compositions containing certain anthraquinone polysulfonamide colorants incorporated therein as toners or colorants. Since the anthraquinone colorant moieties are incorporated into the polymer chain of the polysulfonamide colorants, they are not leachable, sublimable or extractable and do not exude from the thermoplastic compositions. The anthraquinone polysulfonamide colorants may be added to the thermoplastic polymers during production or melt blended with the polymer by conventional techniques to produce transparent thermoplastic compositions useful for a variety of end uses where nonmigrating or nonextractable colorants are needed.
Thermoplastics are typically colored by organic pigments when superior brilliance and tinctorial strength are important. Opacity, however, is introduced into the polymer composition as a result of the insoluble pigment. Also, toxicity considerations have presented chronic problems relative to the use of organic pigments, since some have been shown to be potential carcinogens and to cause contact dermatitis.
Plastics are also colored by using color concentrates consisting of physical admixtures of polymers and colorants (usually solvent dyes). However, the use of such physical admixtures to color polymeric materials such as polyester, e.g., poly(ethylene terephthalate) and blends thereof, present a number of problems:
1. Colorant migration during drying of the colored polyester pellets. PA1 2. Colorant migration during extrusion and colorant accumulation on dies or plateout on rollers which can cause shutdowns for clean-up. Such colorant migration and accumulation result in time consuming and difficult clean-up, particularly when a polymer of another color is subsequently processed on the same equipment. PA1 3. Colorants may not mix well, for example, when using two or more color concentrates to obtain a particular shade. PA1 4. Colorants may diffuse or exude during storage and use of the colored polymeric material. PA1 X and X' are independently Y, --Y--alkylene, --Y--alkylene--Y'--).sub.m, --Y-- alkylene--C.sub.3 -C.sub.8 -cycloalkylene, Y--C.sub.3 -C.sub.8 -cycloalkylene--Y', or Y--alkylene--C.sub.3 -C.sub.8 -cycloalkylene--alkylene--Y', wherein m is 1-3, and Y and Y' are independently --O--, --S--, --N(R)CO--, --N(R)SO.sub.2 --, or--N(R.sub.2)--; PA1 Ar and Ar' are independently a divalent benzene or naphthalene radical which may be substituted with from 1 to 4 substituents which may be the same or different and are selected from C.sub.1 -C.sub.8 alkyl, C.sub.1 -C.sub.8 alkoxy, C.sub.1 -C.sub.8 alkanolyamino, aroylamino, C.sub.1 -C.sub.8 alkylthio and halogen groups; PA1 R and R' are independently hydrogen, C.sub.1-C.sub.8 alkyl, C.sub.3 -C.sub.8 cycloalkyl, heteroaryl or aryl; PA1 R.sub.1 is a divalent organic radical, with the proviso that when R.sub.1 is ethylene, R and R' may be combined to represent an ethylene radical; PA1 R.sub.2 is hydrogen, C.sub.1 -C.sub.8 alkyl, C.sub.3 -C.sub.8 cycloalkyl, C.sub.1 -C.sub.8 alkanoyl, aroyl, C.sub.1 -C.sub.8 alkylsulfonyl, arylsulfonyl, carbamoyl, or sulfamoyl; and n is an integer of from about 3 to about 30. PA1 a) two or more reactive dihalosulfonylanthraquinone intermediates are reacted with one or more diamines to give a colored polysulfonamide; PA1 b) two or more colored polysulfonamides are combined and then added to thermoplastic materials by known methods.
The use of polysulfonamide colorants eliminate or minimize the aforementioned problems associated with the use of conventional dyes and pigments.
2. Description of the Prior Art
It is well-known in the art to color thermoplastic resins by adding pigments or solvent dyes (e.g. see Thomas G. Weber, Editor, Coloring of Plastics, John Wiley and Sons, New York, 1979). The use of pigments, however, is accompanied by undesirable properties such as opacity, dullness of color, low tinctorial strength, etc. Also, difficulties in blending the insoluble pigments uniformly with the thermoplastic resin are encountered. Also, useful for coloring thermoplastic resins are solvent dyes (K. Vendataraman, Editor, The Chemistry of Synthetic Dyes, Vol. 8, Academic Press, New York, 1978, pp 81-131), which give compositions having improved clarity, brightness in hue and high tinctorial strength, but which may lead to dye migration, extraction, etc. from the colored thermoplastic resin. These problems are of particular concern when solvent dyes are used to color flexible resins such as polyvinyl chloride, polyethylene and polypropylene which have low glass transition temperatures.
It is known, also, to prepare solvent soluble nonextractable polymeric aminotriarylmethane dyes having polyester, polycarbonate, polyurethane, or polyethyleneimine backbones and to incorporate them into resins such as polyvinyl chloride, polyvinylidene chloride and acrylic resins such as poly(methyl methacrylate) etc. by solvent blending techniques [S. Mitra (to 3M Corp.), U.S. Pat. No. 4,477,635 (1984)]. Difficulties are encountered in preparing these polymeric colored compounds because a non-colored intermediate aromatic amine containing polymer must be prepared and then the aromatic amine moiety in the polymer structure must be converted into the aminotriarylmethane moiety by further reaction with a diaryl ketone in the presence of condensation catalyst such as phosphorous oxychloride in an inert organic solvent. These previously disclosed polymeric aminotriarylmethane compositions also do not have the requisite thermal stability for use in coloring thermoplastic resins via the more favorable method of melt blending when high temperatures are encountered.
It is further known from U.S. Pat. No. 4,116,923 (1978) to color plastics, in particular polyolefins, with low melting, cross-linked colored polyester compositions containing residues of terephthalic acid, isophthalic acid, or both, a low-molecular weight trimethylol alkane, i.e. 1,1,1-triethylol propane and a copolymerizable colorant, said colorant being present at a level of 0.1-25% by weight. Difficulties are encountered, however, in preparing these highly cross-linked colored polymers as extreme care as regards to the temperature, amount of vacuum, the level of colorant present and the reaction time is necessary to attempt to reproduce the same quality of cross-linked colored polyester composition. Furthermore, these colored polyester compositions are brittle and low melting and may cause deterioration in physical properties of thermoplastic resins when added in quantities sufficient to produce a high level of coloration. Critical in the preparation of these previously disclosed polymers is the achievement of a low degree of polymerization to give a low melting polymer which has adequate solubility characteristics in the resin to be colored; however, to accomplish this the colorant may not be copolymerized, particularly when added at high levels, thus leading to undesirable extractable colorant.
Additionally, it is known to produce polyester color concentrates having colorants copolymerized therein and to use these for coloring thermoplastics (See U.S. Pat. No. 5,032,670; U.S. Pat. No. 5,106,942; WO 92/07913; WO 92113921). The polycondensation reactions required to prepare these polymeric colorants require high temperature conditions (&gt;250.degree. C.) and continuous large scale processing to be cost effective, in contrast to the polysulfonamide colorants of this invention which can be prepared at relatively low temperatures (e.g. usually 100.degree. C., or less) in batch processing equipment.
Finally, it is known (U.S. Pat. No. 5,194,463) to color thermoplastics using polyurethane color concentrates; however, these colorants have the inherent disadvantage of being derived from diisocyanate compounds as one of the reactants, which are known to be toxic and difficult to handle safely on a large scale.
This invention provides thermoplastic compositions comprising one or more thermoplastic materials and one or more anthraquinone polysulfonamide colorants. The colorant may be added during the preparation of the thermoplastic or afterwards via melt blending techniques.